You are what you eat… so goes the saying. And new research into how diet affects your mental health now affirms it: healthy food is a critical factor for a healthy mind.

Arguably the definition of healthy meal may not mean the same thing to everyone. According to researchers, a healthy diet would include raw fruit and vegetables – a better choice for mental health than cooked, canned and processed fruit and vegetables. Their study, published in Frontiers in Psychology, found an individual’s state of good mental health is related to eating higher quality, less-processed food.

“Our research has highlighted that the consumption of fruit and vegetables in their ‘unmodified’ state is more strongly associated with better mental health compared to cooked, canned, (or) processed fruit and vegetables,” says Dr Tamlin Conner, a senior lecturer in psychology at the University of Otago and the study’s lead author.

Conner ties this observation to the possibility that processing fruit and vegetables can lead to diminished nutrient levels.

“This likely limits the delivery of nutrients that are essential for optimal emotional functioning,” Connor says.

The study surveyed 400 young adults from the United States and New Zealand between ages 18 to 25 — an age span when fruit and vegetable consumption is lowest, and risk of mental health disorders is high — to determine how food affects mental health.

Researchers analyzed the group’s consumption of raw versus cooked and processed fruit and vegetables, as well as negative and positive mental health and lifestyle, along with demographic variables that could affect food intake and mental health (for instance sleep, exercise, generally unhealthy diet, chronic health conditions, socioeconomic factors, gender).

“Controlling for the covariates, raw fruit and vegetable consumption predicted lower levels of mental illness symptomology, such as depression, and improved levels of psychological wellbeing including positive mood, life satisfaction and flourishing,” Connor explains. “These mental health benefits were significantly reduced for cooked, canned, and processed fruits and vegetables.”

Connor says he hopes the research can inform diets for depression and other mental health conditions, which are becoming increasingly common as part of holisitic lifestyle approaches to mental health treatment. In the meantime, he and the researchers are sharing the top 10 raw foods for better mental health based on their findings: carrots; bananas; apples; dark, leafy greens like spinach; grapefruit; lettuce; citrus fruits; fresh berries; cucumber; and kiwi fruit.

Bon appétit!